Efficacy and Safety of Cannabis Transdermal Patch for Alleviating Psoriasis Symptoms: Protocol for a Randomized Controlled Trial (CanPatch)

Background Existing topical psoriasis treatments are partially effective or have long-term side effects for a proportion of people with psoriasis; therefore, effective and safe treatment options are required. Cannabidiol, a cannabinoid in Cannabis sativa , reverses the etiology of psoriasis through skin receptors according to in vitro research. Cannabidiol transdermal patches may be an effective treatment for psoriasis, although the efficacy and safety data are limited. Methods and analysis This is a randomized double-blind controlled trial comparing cannabidiol (CBD) with minimal tetrahydrocannabinol (THC) patches with placebo patches (1:1 ratio) daily applied to comparable lesions of each patient with mild to moderate plaque-type psoriasis performed in a university hospital in Thailand (n=60). The primary outcome is the local psoriasis severity index (LPSI). The local severity index of psoriasis, the itch score using the visual analog scale, and adverse events will be evaluated on day 0, 30, 60, and 90 of the study. Furthermore, on days 0 and 90 of this study, biological samples will be taken for the evaluation of the skin, gut, and mouth microbial profile of 50% of randomly selected individuals. Conclusions This study aims to investigate the efficacy and safety of cannabidiol transdermal patches in alleviating the symptoms of psoriasis. We will also examine personal impacts on the efficacy and safety of patches, such as the microbial profile. The results of this study may highlight a novel topical treatment option that reduces suffering in patients with psoriasis. Ethics and dissemination This study was registered with the. The protocol is being considered by the Institutional Review Board of the Faculty of Medicine, Chulalongkorn University. The results of this study will be faithfully presented through conferences or published articles. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial Thai Clinical Trials Registry (TCTR No. 20220518004) ### Funding Statement The study has received financial support from the Thai Traditional Medical Knowledge Fund. The funder has no role in the design, analysis, or writing of the study. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.